a)TRYPTOPHAN FLUORESCENCE IN PHOSPHOFRUCTOKINASE. The temperature dependence of the frequency response of the intrinsic tryptophan emission of phosphofructokinase was studied as a function of emission wavelength. Differential phase measurements were also performed. b) FREQUENCY DOMAIN BACKGROUND SUBTRACTION: Several systems were evaluated for testing the recently developed background subtraction routines. These procedures were successfully implemented for lifetime and dynamic polarization measurements. c)2-photon FCS of FITC-labaled PFK from B. stearothermophilus